Rubber tire for self-propelled



Dec. 129, 1936. E. GoLTsTElN RUBBER TIRE FOR SELF PROPELLED ROADVEHICLES Filed July 6, 1954 Patented Dec. 29, 1936v RUBBER TIRE FORSELF-PROPELLED ROAD VEHICLES Ewald Goltstein, The Hague, NetherlandsAppiication July s, 1934, sei-iai No. 134,029

' In Germany July 20, 1933 4 claims. (ci. 152-14) This inventionrelates'to rubber tires for selffracture by crushing and relativeincompressipropelled road vehicles, more particularly motor bility.Thus, I have found that sago grains effeccars. l tively resistdisintegrationboth in the operation It is known, for the purpose ofrendering a of milling them in as the vacating material with 5 rubbertire non-skidding, especially on a wet the rubber and also in thesubsequent operations road, to incorporate into the tread of the tire ofmanufacture of the tire to completion, with particles of cork which areadapted as the tire the result that the grains remain intact and, beingrolls along the road and wears down at the tread substantiallyincompressible in contrast to the surface, to evacuate said surface andleave the cork particles hitherto used, are in an easily delatter pittedor cavitied with a large number of tachable condition in the rubber soas to'be readl '10 small closely spaced recesses. These recesses are ilydetached therefrom leaving the pits or cavithought to provide receptionspaces for the ready ties referred to in the surface of the tread, asand rapid escape of the water of the wet road the tire rolls along theroad and progressively which would otherwise tend to forma lubricatingwears down. i film between the surface of the tire tread and I havefurther found that it is important in v the road, and it is believedthat this is the theory order to secure the full advantageous effects ofof the remarkable anti-skidding effect obtained the invention to employgrains which, besides bein these known tires. ing of the hardness andrelative incompressibility 'I'he present invention relates to tires ofthis referred to, are of regular form, for example apspecific type, thatis to say the type incorporatproximately round or cylindrical, incontrast to 20 ing in the tread small grains of material (heretheirregular form characteristic of particles of inafter referred to asvacating material) adaptdisintegrated cork. Thus, by employing grains edto fall out bodily or intact at the tread surof regular form in thissense, it is still further face as said surface rolls along the road andensured that the grains shall not disintegrate in progressively wearsdown, leaving the surface the mechanical workingl of the rubber mix inin a cavitied or pitted condition as above dewhich they are incorporatedor in the subsequent scribed. operations performed in the manufacture ofthe It has been found that While tires of this type tire, for thesurface of the grains is devoid of are more or less satisfactory fromthe point of external irregularities or projections tending to 3o viewof anti-skidding capacity, their mileage interengage with thesurrounding rubber. Also, 30

tends to be low. I have investigated this drawthe freedom of the surfaceof the grains from y back and have found that it appears to be dueexternal irregularities or projections enables the to the fact that inthe milling in of the cork grains to avoid becoming interkeyed with theparticles with the rubber of the tread, the cork rubber of the tiretread inthe finished state tends to. fray and become disintegrated onthe of the latter, with the` result that the grains 35 mill. Also, inthe various processes involved in remain more or less loosely held inthe rubber the manufacture of the tire, the particles of cork and aretherefore theAmore free to vacate their become Still further broken 11D0r Wekened- In cavities at the tread surface in conformity with theresult, it is frequently the case that only a .their intended function.I' i 40 relatively small proportion of the total massof In theaccompanying drawing wherein I have 40 Cork Present in the tread iSeffective in the im* illustrated several preferred embodiments of myParting 0f anti'skidding Properties t0 the tire' invention, and whereinthe size of the grains or the balance operating simply in theundesirable granules of Vacating material is shown on a direction toreduce the coherence of the .rubber slightly exaggerated scale for thepurpose of of the tread and correspondingly its resistance illustration,

to dlsim'egratlon by tpe ractwe fag? ressure .f Figure 1 is afragmentary side elevation of a tislllsglnotcgnlrgevges n lalitr; tirecasing which has been subjected to use and to such a degree that its usefor the purpose re wherein there 1s incorporated in the tread porferreato tends to be inconvenient tion thereof substantially round grains ofsago, 50 It is an object of the present invention to avoid Verpceu'macaroni 01 the like' these dimeuities, and 1 accomplish this by em-Fle. 2 1S a View Similar t0 Fig- 1, but Showing ploying, instead ofparticles of cork as hitherto, Substantially Cylindrical grains C )fSagO, Vermigrains of sago or a substance oflike nature, that celli,macaroni or like material incorporated in is to say in respect ofhardness or resistance to the tread portion of the tire casing, 56

Fig. 3 is a transverse sectional view on the line 3-3 of Fig. 1, and

Fig. 4 is a transverse sectional view on the line I--l of Fig. 2.

Referring to the drawing wherein like reference numerals have beenemployed to designate like parts throughout the several views, thenumeral i designates a tire casing of any preferred or desiredconstruction, usually made of rubber or like resilient material. In theform of my invention shown in Figs. 1 and 3, the tire casing I hasembedded therein, preferably at the tread portion only, numeroussubstantially round grains of sago, vermicelli, macaroni or likematerial. Certain of the round grains or granules have evacuated fromthe treadv surface during the use of the tire and thus provide pits orcavities 2 which impart to the-tread surface of the tire the desiredanti-slipping property, those grains or granules remaining below thesurface of the tread being designated by the numeral 3. In the form ofmy invention shown in Figs. 2 and 4, the tire casing I has embeddedtherein, preferably in the tread portion only, numerous substantiallycylindrical grains or granules. of Sago, vermicelli, macaroni, or likematerial. Certain of the substantially cylindrical grains or granuleshave evacuated from the tire surface during the use of the tire and thusprovide pits or cavities 4 which impart to the tread surface of the tirethe desired anti-slipping property, those grains or granules remainingbelow the surface of the tread being designated by the numeral 5.

It will be obvious that in the forms of my invention disclosed herein,the grains or granules of vacating material will be progressivelyexposed to traction with the roadway as the tread surface of the tirecasing wears down, and that the progressive vacating of the grains' orgranules will continuously provide a cavitied or pitted surface.

It should be remarked in connection with the hardness of the grains thatthe latter should not be so hard as to scratch or otherwise injure thepolished rollers of the mills in which the grains are incorporated withthe rubber to form the tire tread or the forming mills through which themix is passed in the manufacture of the tread therefrom. The degree ofhardness characteristic of sago grains meets this requirement eminently,that is to say the conventional sago grain of commerce, while beingsumciently hard to withstand the disintegrating forces imposed upon itinthe mills, is not so hard as to scratch the polished mill rollers.

It will be understood that a wide range of alternative substances tosago may be used for the purposes of the invention. Preferablealternative substances, however, are those which are possessed of thesubstantially homogeneous texture of sago, for example such hardenedpaste products as vermicelli, macaroni and materials of like natureproduced from potato meal, starch or the like.

In this connection, it may be added that these particular substances andalso sago are hygroscopic and possessed of the property of swelling incontact with water, with the result that the small round grains in therubber tend to become wetted with the water of the road and the water sotaken up becomesconveyed to the interface between the surface of thegrain and the wall of the cavity in the rubber in which the grain isheld. By this means, the surface of the grain becomes in a certainmeasure lubricated, which still further assists in the vacating of thegrain from the cavity in the rubber. In addition, the grain swellsslightly against the resilience of the surrounding rubber so as ineffect to be under slight pressure from the wall of the cavity tendingto project the lubricated grain out therefrom as soon as the cavity hasbecome sufficiently opened by the wearing down of the tire coupled withthe stretch of the rubber of the tread surface as the tire rolls alongthe road.

An example of one embodiment of the invention will now be described.

100v pounds of vulcanizable rubber composition of a type customary forthe treads of pneumatic motor-car wheel tires are admixed upon a rollingmill with 7 pounds of sago grains. The mixing is continued until theincorporation of the sago grains with the rubbercomposition is asuniform as possible. The resulting mixture 'is then ready for use in themanufacture of the tire tread. which may be produced by any of the wellknown processes in the art.

What I claim and desire to secure by Letters Patent of the United Statesisz- 1. A rubber tire of the type incorporating in the tread grains ofvacating material adapted in the use pf the tire to fall out at thetread surface and to leave the latter in a pitted condition as hereindescribed, wherein the vacating material consists of approximately roundgrains of sago.

2. A rubber tire of the type incorporating in the tread grains ofvacating material adapted in the use of the tire to fall out at thetread surface and to lea've the latter in a pitted condition as hereindescribed, wherein the vacating material consists of approximately roundgrains of a substance selected from the following group: sago.vermicelli, macaroni. v

3. A rubber tire of the type incorporating in the tread grains ofvacating material adapted in the use of the tire to fall out at thetread surface and to leave the latter in a pitted condition as hereindescribed, wherein the vacating material consists of approximatelycylindrical grains of sago.

4. A rubber tire of the type incorporating in the tread grains ofvacating material adapted in the use of the tire to fall out at thetread surface and to leave the latter in a pitted condition as hereindescribed, wherein the vacating material consists of approximatelycylindrical grains ofa substance selected from the following group:sago, vermicelli, macaroni.

EWALD GoL'rs'rmm.

